1. Field of the Invention
The present invention sets forth a loudspeaker which propagates coherent sound waves spherically in the manner of point source. The speaker has a relatively high frequency driver and a relatively low frequency driver, both mounted in a housing that in addition to being a structural support performs the additional function of directing and delivering sound. Applications of the invention include consumer, commercial, and institutional systems for reproducing and broadcasting sound, especially musical sound.
2. Description of the Prior Art
In the field of sound reproduction, and more particularly in the field of musical reproduction, it is desirable to reproduce sound in a manner as close to the original sound as is possible. Most sound reproduction systems employ one or more drivers both as transducers for generating sound from electrical signals, and to propagate the reproduced sound. The drivers, as combined into a self-contained speaker, must reproduce sound as faithfully as possible and project that sound universally in all directions.
The prior art has proposed speaker arrangements for achieving omnidirectional sound propagation. Examples are seen in U.S. Pat. No. 3,483,945, issued to Stanley Michael on Dec. 16, 1969, U.S. Pat. No. 3,961,684, issued to Stanley H. Michael et al. on Jun. 8, 1976, U.S. Pat. No. 5,115,882, issued to D. Grier Woody on May 26, 1992, U.S. Pat. No. 5,086,871, issued to Alain Barbe on Feb. 11, 1992, U.S. Pat. No. 5,227,591, issued to Timo Tarkkonen on Jul. 13, 1993, U.S. Pat. No. 5,436,976, issued to Donald J. Dougherty on Jul. 25, 1995, and U.S. Pat. No. 5,451,726, issued to Ted L. Haugum on Sep. 19, 1995. In each case, the subject speaker lacks the precise arrangement of drivers and chambers contained within a cylindrical housing, as seen in the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention sets forth a construction for a very small loudspeaker for producing sound waves from electrical signals which sound waves are propagated in time and phase coherent manner. The novel loudspeaker reproduces with great fidelity sound which is to be directed to a human audience inside a building or other enclosure. In particular, the novel loudspeaker is suited for consumer sound systems including audiovisual equipment, music reproduction equipment, and sound synthesizing equipment, employing sound chambers which are remarkably small for the quality and volume of the sound produced.
The novel loudspeaker has, in various embodiments, two or three speakers mounted in a common cylindrical enclosure. The enclosure serves both as a structural member and also to form resonant chambers for influencing and propagating sound. Configuration and characteristics of the enclosure and its components are selected to maximize effectiveness of the loudspeaker.
The enclosure is a sound reflective cylinder divided into resonant chambers. These chambers are separated in one embodiment by the lower frequency sound driver of two sound drivers provided in the loudspeaker. In an embodiment incorporating three sound drivers, resonant chambers are separated by the lower two sound drivers and an open intermediate chamber. The relatively low frequency sound driver directs its sound downwardly into the lowermost of the chambers. This chamber optionally opens to the outside atmosphere by a port in the lateral wall of the chamber. Optionally, the speaker is mounted on legs, and the port is formed in the floor of the chamber.
The upper chamber serves as a reverberation chamber for both the relatively high frequency sound driver, which is upwardly directed, as well as for a relatively lower frequency sound driver. High frequency sound passes through the high frequency driver, and escapes upwardly to the outside.
Sound quality and propagation characteristics arise from resonance and other phenomena resulting from relationship of sound drivers to one another and to the housing, and from acoustic properties of cylindrical configuration of the housing and its division into upper and lower chambers.
Optionally, the loudspeaker includes two pairs or sets of input signal terminals and a switch for selecting between the two pairs or sets of input signal terminals. In a further option, the loudspeaker incorporates an amplifier so that input signal sources such as personal computers are compatible with the loudspeaker.
The novel loudspeaker includes a crossover network, which is mounted on the floor of the lower chamber. Interior surfaces of the chambers of the speaker are preferably lined with acoustic padding. The exterior of the housing is covered with grille cloth which passes sound with minimal dampening and distortion.
Accordingly, it is one object of the invention to provide a loudspeaker which reproduces sound in time and phase coherent waves.
It is another object of the invention to provide a high fidelity speaker which is very small and compact for its sound output.
It is a further object of the invention that the novel loudspeaker be capable of ready connection to different input signal sources.
Still another object of the invention is to provide a high fidelity compact speaker which is compatible with personal computers as sources of sound input signals.
An additional object of the invention is to provide high fidelity sound employing only two sound drivers.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.